In a tire recapping process utilizing precured tread rubber the tread area of tire casing is first buffed to a smooth surface and then is covered by a thin layer of uncured bonding rubber. Thereafter, the bonding layer is covered by a precured tread rubber strip which is normally stitched or stapled in place on the tire. The entire tire assembly is then covered with a flexible envelope which extends over the tread area and downwardly along both tire sidewalls. An apparatus must then be utilized to seal both sides of the envelope against the outer tire surface, preferably in the bead area of the tire, before the assembly is placed in a chamber for a curing period.
Previous arrangements for accomplishing the envelope sealing in various tire recapping apparatus are shown in U.S. Pat. Nos. 4,274,897 and 4,624,732 both of which are assigned to the assignee of the present invention. In the former patent, a pair of grilles are utilized to press the envelope against the sidewalls of the tire by means of a series of coiled springs. In the latter patent a pair of ring members which are shaped to press against the envelope in the bead area of the tire being recapped are also held together by spring members. In another prior art apparatus shown in U.S. Pat. No. 4,579,619, a series of clamps are attached to each of a pair of ring members to secure and seal the envelope around each tire bead area.
While the aforesaid prior art arrangements provide satisfactory results for many recapping operations, the installation of the various apparatus components in carrying out the recapping process was often excessively time-consuming. One object of the present invention is to provide an improved recapping apparatus that will solve this problem and enable a single workman to install an envelope sealing apparatus on a tire recapping assembly quickly without the need for making multiple time-consuming connections and adjustments of moveable components.
Another object of the present invention is to provide an improved apparatus for sealing an envelope in a tire recapping process that requires the closure of only one moveable element in order to cause full sealing contact on the outer bead area of the tire and backup pressure at several locations on the inner bead area surface of the tire.
Still another object of the invention is to provide an apparatus for sealing an envelope in a precured rubber recapping process that is particularly well adapted for ease and economy of manufacture.